<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>

  <body>
    <script>
      // 1.类的继承
      // class Father {
      //     constructor() {

      //     }
      //     money() {
      //         console.log(100);
      //     }
      // }
      // class Son extends Father {

      // }
      // var son = new Son();
      // son.money();

      class Father {
        constructor(x, y) {
          this.x = x
          this.y = y
        }
        sum() {
          console.log(this.x + this.y)
        }
      }
      class Son extends Father {
        constructor(x, y) {
          super(x, y) //调用了父类中得构造函数
        }
      }
      var son = new Son(1, 2)
      var son1 = new Son(11, 22)
      son.sum() // 3
      son1.sum() // 33
    </script>
  </body>
</html>
